Networks sometimes require software and/or hardware maintenance, e.g. component or module repair, replacement or upgrade, to their access servers. This generally requires reloading software, which means taking one or more disk drives off-line, etc. It often requires power cycling, which does the same thing. Because one or more users/clients are almost always connected to the access servers, reloading or power cycling the access servers to perform the upgrade denies service to the connected users/clients. For the same reason, service personnel are required to schedule such upgrades during inconvenient, off-peak hours, to minimize the number of connected users who are affected.